The present invention relates to cleaning devices and, more particularly, to devices for separating heavier impurities from solid bodies in a fluid flow.
The devices for separating heavier impurities from solid bodies in a fluid flow will render most efficient service for separating heavier impurities from roots and tubers, such as beets and potatoes in beet-sugar, potato-starch making industries, and in beet and potato alcohol production.
The present invention can be utilized in agriculture for cleaning roots and tubers in the forage making, in canning industry, in public catering with centralized cleaning of roots and tubers and in other branches of industry where there is a need for separating impurities which are heavier than the main lump material conveyed by a fluid flow.
At present, with the rapid development of mechanization in harvesting root and tuber crops there is an evergrowing demand for highly efficient and economical devices for cleaning the roots and tubers from foreign matter, such as stones and sand.
Widely known in the prior art is a device for separating heavier impurities from solid bodies in a fluid flow. This device comprises a screen drum mounted horizontally in a casing and it is secured by struts on a shaft.
The casing of the device is fastened to a hydraulic conveyor, has a trough-like shape and is formed by a part of a stepped cylinder.
Spirally-arranged ribs are secured to the external and internal surfaces of the screen drum.
The ribs fastened to the internal surface of the drum are intended to move the larger impurities settling in the drum against the flow of fluid delivered by the hydraulic conveyor. The ribs secured to the external wall of the drum catch the impurities which fall out through holes in the screen side wall of the drum and move them over the internal surface of the casing.
Fastened to the drum face at the inlet of the fluid delivered by the hydraulic conveyor and carrying solid bodies and impurities is an appliance arranged coaxially with said drum and designed to separate, receive and unload the impurities.
The basic disadvantage of the known device for separating heavier impurities from solid bodies in a fluid flow is in that the efficiency of separation by the device drops sharply with an increase in the quantity of the solid bodies carried by the fluid flow.
This is attributable to the fact that the ribs secured to the internal surface of the screen drum and protruding above said surface offer an additional resistance to the flow of fluid carrying the solid bodies and thus reduce the velocity of the flow and cause the solid bodies carried by the fluid to settle in the drum. This, in turn, hinders the conveyance of larger impurities by the internal ribs to the applicance for separating, receiving and unloading the impurities. The impurities that have settled in the drum during its rotation are gradually moved along the flow together with the solid bodies which reduces considerably the efficiency of the device.
Another no less important disadvantage of the prior art device lies in that the concentration of the solid bodies in the flow of fluid moving inside the drum becomes higher.
This is attributable to the fact that part of the fluid carrying the solid bodies to be cleaned passes beyond the drum through the gaps between the external ribs of the drum and the casing.
The resistance to the movement of such a flow in the drum grows, thus increasingly reducing the efficiency of the device.